Pros

Embedded Alexa voice service.

Remote room sensor.

Works with other connected devices.

Easy to install.

Cons

Pricey.

Middling audio quality.

When we reviewed the Ecobee3 in 2015 it earned our Editors' Choice for its sleek design, numerous features, and ease of use. We also loved the inclusion of a remote sensor to help reduce hot or cold spots in different rooms. We're happy to report that the new Ecobee4 ($249) boasts all the same features as it predecessor, and more, thanks to the addition of built-in Amazon Alexa voice service capabilities. That means you can have the thermostat do everything that the Amazon Echo and its siblings can, such as control smart devices, shop, play music, and hear the latest news and weather, all using Alexa voice commands. This addition makes it our Editors' Choice for smart thermostats.

Design and Features

The Ecobee4 looks very similar to the Ecobee3, but there are subtle differences. It has the same black faceplate and 3.5-inch color touch display, but at 4.2 by 4.2 by 1.0 inches (HWD) it's a bit larger. It also has an LED strip on its top edge that glows blue when you begin a voice command with "Alexa," and red when the built-in microphone is turned off. There's a speaker embedded in the back of the housing. The back plate contains 12 terminal connections for connecting to heating and air conditioning, humidifiers, dehumidifiers, air ventilation devices, and other HVAC accessories.

Under the hood are temperature, humidity, motion, and proximity sensors. The motion and proximity sensors tell the thermostat if you are home or away, allowing it to switch to a preset temperature setting. There's also 802.11n Wi-Fi circuitry, built-in microphones, and far-field voice recognition technology that allows you to issue Alexa voice commands from across the room. As with the Ecobee3, the Ecobee4 comes with a remote room sensor that communicates with the thermostat to ensure that the temperature in the room where you place it is consistent with the thermostat's target temperature. If you want to add more sensors you can buy a two-pack for $79.

You can use the thermostat's touch display, an Android or iOS mobile app, or a web dashboard to set temperatures, create heating and cooling schedules, and adjust comfort settings. The app opens to a home screen that displays the current temperature and a slider for setting the target temperature. When I reviewed the Ecobee3 I found the slider to be a bit too sensitive, but had no such issues with the Ecobee4.

Nest Thermostat E

Lux/Geo Wi-Fi Thermostat

Below the current temperature are four icons, including a Settings icon with tabs for System, where you can enable and disable heating, cooling, and fans; Sensors, where you can enable or disable the Smart Home/Away feature that overrides your heating/cooling schedule if the thermostat senses that nobody is home; and Schedule, which allows you to create daily and weekly heating/cooling schedules. The Comfort Settings menu lets you set temperature thresholds for when you are home and away, and you can set temperatures for when you're asleep and for when you are on vacation. The Reminders & Alerts menu lets you set up things like low and high temperature alerts, low and high humidity alerts, and maintenance reminders.

Tapping the weather icon displays a screen with the current weather conditions along with a five-day forecast. The gear icon opens the Quick Changes screen where you can switch from Home to Away modes (and vice versa) instantly, and the microphone icon takes you to a screen where you can adjust the volume of the speaker and enable or disable the microphone.

As with previous models, the Ecobee4 offers a Home IQ feature, which is only available on the web app. It provides colorful graphs that show you a historical track of HVAC usage and lets you see what the outside temperature was during a specific time to see how it impacted your HVAC system.

The Ecobee4 supports IFTTT applets, which allow it to work with numerous smart home devices. It addition to Alexa voice commands you can control it using Siri voice commands and HomeKit devices.

Installation and Performance

As with the Ecobee3, the Ecobee4 is relatively easy to install thanks to a highly detailed installation guide, but if you're not comfortable with handling electrical wiring (even low-voltage wiring), have a professional install the thermostat.

Start by turning off the breaker that controls your thermostat's power and removing the cover from your old thermostat. Take a picture of the wiring for future reference before disconnecting them from the old thermostat. If you mark the wires with the included labels, the installation will be that much easier. Attach the Ecobee base plate to the wall using the included mounting screws, making sure it is level using the built-in level tool. If your system has a C wire (common wire), attach the wires to their corresponding terminals on the base plate. If you don't have a C wire, use the included PEK (Power Extender Kit) and follow the wiring instructions in the printed guide. Once wired, snap the thermostat onto the base plate by gently pressing it into place.

Installing the sensor is also easy. When I stood in front of the thermostat and pulled the plastic battery tab from the sensor it was immediately identified and added to the app.

The Ecobee4 performed flawlessly in my tests. It reacted instantly to my temperature change commands using the mobile app, the web dashboard, and the touch screen. It followed my daily schedules without missing a beat, and had no trouble following my Alexa and Siri voice commands to adjust temperature settings. A HomeKit scene to have the thermostat switch to Sleep mode and turn on the front porch light worked like a charm, as did my IFTTT applet to set and hold the temperature at 68 when the Weather Underground reported a temperature below 58 degrees. The back bedroom with the remote sensor maintained the exact temperature as the room with the Ecobee4 thermostat, and I received push alerts whenever the temperature or humidity reached a certain threshold.

The Ecobee4 provided full Alexa functionality in my tests, playing music on demand, delivering the latest news and game scores, and controlling other devices including a Haiku fan and Vivint lights, using Alexa skills. My only gripe is that the built-in speaker, while adequately loud, sounds a bit tinny and lacks the bass response I'm used to with my original Amazon Echo.

Conclusions

You'll pay more for the Ecobee4 than you will for a traditional non-connected thermostat, but that's true with nearly all smart devices. And that said, you get your money's worth with this thermostat, especially if you want to take advantage of Amazon's Alexa voice service. Even if you don't, the Ecobee4 offers flexible scheduling, a well-designed mobile app and web interface, remote room sensors, and motion-sensing technology to help save you money when you're not home. It's a snap to install and lets you track your energy usage, and it works with a number of third-party smart devices. All this makes the Ecobee4 a shoo-in as our new Editors' Choice for smart thermostats.

If you prefer a thermostat that creates a heating and cooling schedule based on your daily activities, check out the Nest Learning Thermostat (3rd Generation), another strong choice. It doesn't offer remote room sensors or have built-in Alexa, but you can control it using Alexa and Google Assistant voice commands if you already have an Echo or Google Home speaker, and it works with plenty of other connected devices. If you're looking to save some money, the $169 Nest Thermostat E is another good alternative that has most of the features of its pricier sibling, but fewer wiring terminals.

About John R. Delaney

As a Contributing Editor for PCMag, John Delaney has been testing and reviewing monitors, TVs, PCs, networking and smart home gear, and other assorted hardware and peripherals for almost 20 years. A 13-year veteran of PC Magazine's Labs (most recently as Director of Operations), John was responsible for the recruitment, training and management of the Labs technical staff, as well as evaluating and maintaining the integrity of the Labs testing machines and procedures. Prior to joining Ziff Davis, John spent six years in retail operations for Federated Stores, Inc. before accepting a purchasing position with Morris Decision Systems, one of New York's first value-added resellers of the original IBM PC. For the next five years, he was responsible for buying and configuring IBM PC, XT and AT desktops for many of New York's financial institutions. He then worked for the now defunct ComputerLand chain of PC dealers before joining PC Magazine in 1987.

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